1. Field of Invention
The present invention relates to a device and method for harvesting or collecting brine shrimp eggs from a water body. More specifically, the present invention relates to a device for extracting brine shrimp eggs at the surface of the water body.
2. Prior Art
Brine shrimp have been harvested for many years and are used as fish food on a commercial basis. See, for example, U.S. Pat. No. 3,768,193 by London which discloses a raft and a skimming net. The net is supported by pontoon floats and is utilized to capture the small brine shrimp from their water habitat. The wedge shaped collecting structure shown in London is also disclosed in U.S. Pat. No. 2,786,592 of Miller and 2,832,168 of Brown. This wedge construction assists in channeling the material to be harvested. U.S. Pat. No. 4,458,621 by DeClifford is a more recent disclosure showing another device and method for collecting marine life somewhat related to the previous patents cited.
During the past three decades, collection of brine shrimp eggs has been accomplished, with the eggs being washed, dried and vacuum packed for storage. These eggs can be reconstituted and hatched by incubation in salt water at 80 to 85 degrees F. The eggs may be nurtured to young brine shrimp, which are used as fish food for commercial hatcheries and similar businesses.
The methods and structure shown in the London patent are not effective for gathering brine shrimp eggs. For example, there are approximately seven million brine shrimp eggs in a single ounce. The use of nets and similar devices for collection of brine shrimp eggs would be totally meaningless. The eggs would pass through the nets with little success in collection.
Accordingly, prior art collection of brine shrimp eggs has been accomplished by collecting the eggs left along beach surface area. Such collection has been by shovel or other type of scraper. The thickness of eggs deposited on the beach depends upon the thickness of eggs floating at the water surface. Typically, the floating eggs occupy the top one quarter inch of water and may accumulate to depths on the beach of one half inch or more.
The unique character of brine shrimp eggs on a salt water surface has discouraged attempts to skim them in a manner similar to skimming oil slicks or other surfacefloating material. Because such eggs are so small (7 million per ounce) they are extremely difficult to deal with as a solid material. A major portion will pass through nets and other forms of screening devices. On the other hand, they tend to agglomerate when concentrated and in close contact so that they lose their fluid character. For this reason, a standard skimming device used for extracting oil slicks is useless for gathering brine shrimp eggs.
It has been discovered that the challenge in harvesting brine shrimp eggs is to develop an economical way of concentrating them in bags for commercial utilization. Gathering them from the beach by scoops or shovels is difficult because they have lost their flowable character. Netting or screening them from the water surface is ineffectual because of their very small size. In actual attempts to utilize an oil skimming device to concentrate, it was found that the eggs cling together and solidify when concentrated, thereby becoming very difficult to pump. The typical floating surface leveling door used with oil skimmers does not function in the brine shrimp egg environment. In addition to the inability of the oil skimming device to handle jamming of eggs at the pump inlet, it did not provide the control necessary to adjust the amount of water taken with the eggs. With too much heavy salt water, it is impractical to filter out the eggs in the collection sacks. Too little water results in agglomeration of eggs with resultant failure of the pumping system.